Method and machine for manufacture of carbon paper



July 9, 1968 J. T. CROW ET AL 3,392,041

METHOD AND MACHINE FOR MANUFACTURE OF CARBON PAPER Filed March 29, 1965 2 Sheets-Sheet 1 INVENTOR BY am, QMrWZZZ ATTORNEYS July 9, 1968 J. r. CROW ET AL 3,392,041

METHOD AND MACHINE FOR MANUFACTURE OF CARBON PAPER 2 Sheets-Sheet 2 Filed March 29, 1965 L,TM-L

Warm, BY z l;

w w P ATTORNEY 5 United States Patent 3,392,641 METHOD AND MACHINE FOR l't IAYUFACTURE OF CARBON PAPER John T. Crow and Emil A. DLuhy, Youngstown, N.Y.,

assignors to Moore Business Forms, Inc., Niagara Falls,

N.Y., a corporation of Delaware Filed Mar. 29, 1965, Ser. No. 443,229 Claims. (Cl. 117--36.1)

This invention relates to methods and means for coating carbon paper for transfer purpos s, and more particularly to those which are involved in applying partial carbon composition coatings on webs of tissue.

Carbon ink is coated on tissue webs to provide transer papers by mechanism somewhat similar to the ink fountain installations on printing presses, the essential elements of such mechanism being an ink fountain, a fountain roll, and an applicator or print roll, the last named roll partaking of the functions of both the form roll and the plate cylinder of a printing press, this print roll comprising the means which is brought into rolling contact with the moving web of tissue to deposit an even regulated coating or film of carbon composition thereon.

However, no doctor rolls are usually employed and, in this particular embodiment, a metering roll is used to regulate the thickness of the coating of molten ink composition to be delivered by the fountain roll to the print roll. Also, a wiping tool or instrumentality is employed to remove the carbon composition from the fountain roll at portions corresponding to areas which are to be left uncoated on the web.

The even metered coating of carbon formulation which is applied to the entire surface of the tissue web in ordinary practice, acts somewhat as a lubricant which prevents the paper web from abrading the rubber print roll. However, in selective partial coating of the Web, where a wiper roll or blade removes the required width of strip of coating from the fountain roll and consequently from the applicator or print roll, the removal of the ink from such area leaves the print roll open to abrasion. Thus, in a short time the roll is worn sufficiently so that on a subsequent order, when a full width coating is to be applied, or where the strip coating pattern is different, the Worn area shows up as a thicker coating on the web, and at the same time streaks appear along the lines which would correspond to the boundary edges of the previous uncoated strips.

This requires that the applicator roll be removed and re-ground at frequent intervals.

The general object of the present invention is to pro vide a novel and improved coating device and method of coating of carbon tissue webs which can be used alternately to produce fully coated and strip coated webs, and which will eliminate the difficulties attendant upon the abrasion of the rolls experienced in the common procedures now employed.

In the preferred embodiments of the invention, the beneficial effects are obtained by oscillating the applicator or print roll alternately in opposite axial directions, but at an exceedingly slow rate as compared with the speed of production as determined by the angular speed of rota tion of the rolls and the corresponding linear delivery feed of the web.

Other objects and features of novelty will be apparent from the following specification when read in connection with the accompanying drawings in which one embodiment of the invention is illustrated by way of example.

In the drawings:

FIGURE 1 is a perspective view in quite schematic form of the essential elements and mechanisms of a coating machine embodying the principles of the invention;

FIGURE 2 is a highly exaggerated diagrammatic view in elevation of a print roll and adjacent tissue web showing 3,392,041 Patented July 9, 1968 the streak configuration resulting in the conventional case of a non-oscillated roll;

FIGURE 3 is a fragmentary view of a print roll showing in a highly exaggerated way the resulting abrasion wear on a roll which is not oscillated; and

FIGURE 4 is a similar view of a roll which has been oscillated according to the present invention.

In the rather diagrammatic showing in FIGURE 1, the supporting frame of the coating mechanism is represented by the two side frame members 11 and 12. A preferably chrome coated fountain roll is shown at 15 as having a shaft 16v with appropriate bearings in the side frame mem' bers. A preferably rubber covered metering roll 18 has its shaft 19 mounted in suitable bearings in the side frame and in adjustable rolling contact with the fountain roll.

The remainder of the details of the fountain in this case have been omitted for simplicity of illustration, but it is understood that any appropriate or conventional relationship of the fountain of carbon composition with the fountain and metering rolls may be employed.

A rubber covered applicator or print roll has its axle 26- mounted in bearings 27 and 28 carried by the side frame members, for both rotary and axial movement with respect to the frame, and being in rolling contact with the fountain roll.

Finally in the sequence of members involved in the coating process, there is the web of tissue 30 to which the thin carbon film is applied. The continuous web is moved at a high speed in contact with the rapidly rotating print roll. In should be necessary only to indicate the usual inter-connection of the driving means in a purely diagrammatic fashion and thus in FIGURE 1 the roll 32 is intended to generically represent the means for feeding the web 39. A pinion 20, suitably rotatably mounted on the side frame member 11 has a shaft 21 and is in mesh with the gear 22 carried upon the end of the metering roll shaft 19. A gear 23 is carried upon the end of the fountain roll shaft 16 and meshes with both the gear 22 and a wider gear 24 fixed to an end of the print roll shaft 26.

In order to indicate the operatively connected synchronized drive means a block M represents a common source of drive for the ink applying rolls and the web.

As thus far described, the machine is generically depicted in condition for applying a thin coating of carbon to the surface of the Web 30 substantially throughout its entire width, and for this simple purpose would need no further serious modification.

However, when it is desired to eliminate certain portions of the carbon coating on the web 30, there is provided wiping mechanism represented generically in the present illustration as a wiping blade member 35 carried in any suitable manner by the frame and having its wiping edge applied to the surface of the fountain roll 15 so as to remove a stripe of ink indicated at 36. A trough or guide 38 may be provided to discharge the removed coating. Obviously, with the coating removed along the stripe 36, the film transferred to the print roll 25 will be interrupted by the annular bare stripe 39, and correspondingly the web 30 will be imprinted with a broad coated area td, a narrow marginal coated area 41, and an uncoated stripe area 42.

For purposes of future reference, the broad coated area of the print roll 25 is indicated at 39a, the narrow marginal coated area at 391').

Now before describing the means for axially oscillating the print roll 25, it will be well to indicate the difficulties which arise in selectively printing carbon composition upon webs by means of the partially coated print roll. One theory is that in the course of production with a full coating on the web, the ink acts as a lubricant to keep the paper web from abrading the rubber roll. In

strip coating, however, where areas of ditferent widths are left uncoated, the removal of the ink from this area on the applicator or print roll leaves it open to abrasion and in a short time the roll is worn sufficiently so that on a subsequent order, when a full coating is needed, or where the strip coating is in a different position, the worn area shows up as a thicker coating on the paper web and, at the same time, streaks appear in the positions that would correspond to the previous edges of the uncoated strips. This means that the applicator or print roll must be removed and re-ground and since this roll will abrade sufiiciently to cause trouble in a very short period of time, this re-grinding and renewing is quite uneconomical.

Referring now to FIGURE 2 of the drawings, the print roll will be recognized at 25 and the paper Web at 30. In a highly magnified and exaggerated form, the gap shown at x represents a worn portion of the print roll 25 which would occur at the lateral margins of the strip 39 where it adjoins the coated areas 39a and 39b. The erosion or wear along this circular line has the effect on a subsequent run of uninterrupted web coating of producing a streak pattern suggested in FIGURE 2 where average proper deposits of coating are applied to the areas a and b on either side of the abraded line, and just inwardly of these normal average deposits there appear stripes c and a of very light deposits, these being aligned with the edges 2 and f of the abraded or worn mark on the print roll.

Adjacent to these two practically bare stripes c and d are heavy deposit stripes g and h of approximately the same width as the light stripes c and d. Then inside of these marks appears another stripe i of average deposit similar to the broad normal areas a and b. A plausible reason for the appearance of these light and heavy stripes is that at the point of ink transfer from the fountain roll to the print roll, high and low pressure areas cause axial fiow of the ink. At the outer edge of the abraded mark,

a high pressure is thought to develop that would cause the ink to flow inwardly toward the center of the abraded mark and thus produce the light and dark stripes. Toward the center of the abraded area, the pressure is once again equalized and an average deposit results.

It is understood that the peculiar streaked pattern indicated in FIGURE 2 applies to the resulting coating of the web 30 over an area which is to be completely covered, and which results from a worn or abraded mark on the roll 25 due to previous abrasion by the paper under conditions of partial or stripe coating without oscillation of the roll.

Now to cure this, applicant has discovered that if the print roll 25 is given a very slow axial oscillation as compared with the general speed of movement of the rolls and the web in producing the carbon paper, this effect is eliminated and subsequent all-over coatings or coatings according to a different pattern may be effected without the undesirable streaking described.

For this purpose the print roll shaft 26 is additionally provided with a cam disc 50 which may be fixed alongside the wide toothed gear 24. A circular groove 51 is formed in the periphery of the disc 50 and inserted within the groove is an eccentric crank pin 52 which is carried by the rotatable shaft 53 driven from the speed reducing gear box 55 which is synchronously driven by the same source of motion M provided for the general drive of the machine.

Of course, the cylindrical cam groove 55 has zero displacement axially, but the pin 52 has an eccentricity in this specific example of say one-half inch, giving a total resulting axial displacement of the shaft 26 and the print roll 25 of one inch, which of course may be varied within reasonable limits.

Now if the oscillation were of any substantial frequency, smearing of the imprint might occur and possibly a blurring of the margins of the uncoated stripes. However, it is desired that the shaft 53 and consequently the eccentric pin 52 complete only one revolution for say approximately every 200 to 2,000 or more revolutions of the print cylinder. The length of stroke of the oscillation is determined by the amount of eccentricity with which the pin 52 is mounted with respect to the shaft 53 of the gear reducer, a one inch stroke requiring one-half inch eccentricity as mentioned. Assuming a 800:1 ratio, a one inch stroke, and say a two and one-half foot print roll circumference, the axial displacement of the print roll would be equal to only 0.001 inch per foot of print roll surface or web surface travel. Even at the suggested lower 200:1 ratio, there would be only a 0.004 inch lateral displacement per foot, or 0.010 inch per print roll revolution, which would be far toosmall to detect as a weave or waver in the uncoated strip.

In this connection, it is to be continually borne in mind that the stripe is constantly being removed during each revolution of the fountain roll and that the error is not cumulative, and that the print roll is the only one that oscillates, the web and the other rolls remaining in fixed lateral positions.

For another example of the operation of the device, we can assume that the roll is oscillated a total of one inch and the timing for a complete oscillation is three minutes. Assume that the paper is running through the coating machine at 1,000 feet per minute and the print roll moves one inch in one direction in one and one-half minutes, a simple calculation will show that the roll will travel only 0.00066 inch during one foot of travel of the paper. Assuming the print roll to be twelve inches in diameter and that the carbon removal means is on the opposite side from the point of application of the ink to the paper, and since the speed of the print roll is the same as the paper speed, it can be seen that the application or print roll will move sideways a total of 0.00099 inch while the roll rotates from the strip coating removal point to the application point on the paper, or approximately one thousandth of an inch. This occurs while the oscillation is in one direction and will remain constant; that is, the error will not accumulate. For the total period of oscillation, the error would be double or approximately two thousandths of an inch. This of course is much too small to be of any consideration whatsoever, since it is far below the tolerances for the usual weave of a web of paper passing through a machine of this type.

Now referring to FIGURES 3 and 4 of the drawings, FIGURE 3 illustrates the relative depth of Wear that would be experienced by a non-oscillated print roll and FIGURE 4 represents the relative depth of wear that would be experienced by an oscillated print roll. It is to be noted that the actual volume of rubber abraded from both of these rolls is substantially the same but that the depth of the abrasion which causes the objectionable marks illustrated in FIGURE 2 is limited by the oscillation. The actual width of the uncoated stripe is again indicated in both of these figures at 39 and the depth of abrasion in the case of the unoscillated roll is suggested in a highly exaggerated way at 60. The wear on the oscillated roll as shown in FIGURE 4 would be spread over a much wider area as indicated at 61, the uncoated strip width still being indicated at 39 in this figure.

As an illustration, let it be assumed that a one-eighth inch strip with no oscillation of the print roll 25 wears a groove one-eighth inch wide and 0.0005 inch deep while 20,000 yards of tissue is being coated; and that this is enough to leave a mark on the next job when the striping tool is either removed or moved to another location. If the print roll had been oscillated one inch during this period the depth of wear would be in accordance with the following derivation.

The following formula has been developed in which D is the 'depth of the groove with oscillation and D is the depth of the groove without oscillation. Thus:

D Length of Oscillation l- Uncoated Strip Width D Uncoated Strip Width 0.125 D Length of Oscillation *0'O005X 1.0

This would indicate that eight times as much yardage of web could be produced before an objectionable streak would appear on the product. Furthermore, because of the oscillation, the amount of wear at the extreme ends would be still further reduced and there would be no sharply defined shoulders to cause pressure differentials and the resulting disturbing ink flow as suggested in the pattern represented in FIGURE 2.

It is understood that various changes and modifications may be made in the embodiments of the invention illustrated and described herein Without departing from the scope thereof as determined by the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A machine for applying carbon composition to webs of tissue for the manufacture of carbon paper with predetermined uncoated areas, said machine comprising a supporting frame, a fountain device carried by said frame and including a rotatably mounted fountain roll, a print roll, means for feeding a web of tissue past said print roll rotatable in synchronized rolling contact with said fountain roll and also with respect to said web to pick up a film of carbon composition from said fountain roll and apply it to said web, and means for oscillating said print roll with respect to the fountain roll and web and in the direction of its own axis and at an extremely slow rate as compared with the rate of rotation of the rolls and the rate of linear feed of the web, means for removing a portion of said film from certain of said rolls to provide a desired pattern of partial coating application to the web and means for driving said rolls, web feeding means, and oscillating means.

2. A machine for applying carbon composition to webs of tissue for the manufacture of carbon paper with pre determined uncoated areas, said machine comprising a supporting frame, a fountain device carried by said frame and comprising a rotatably mounted metal surfaced fountain roll and a cooperating metering roll rotatably in contact with said fountain roll, a rubber-coated print roll, means for feeding a web of tissue past said print roll rotatable in synchronized rolling contact with said fountain roll and also with respect to said web to pick up a film of carbon composition from said fountain roll and apply it to said web, and means for oscillating said print roll with respect to the fountain roll and web and in the direction of its own axis and at an extremely slow rate as compared with the rate of rotation of the rolls and the rate of linear feed of the web, means for removing a stripe of said film from said fountain roll to provide a desired pattern of partial coating application to the web, and means for driving said rolls, web feeding means, and oscillating means.

6 3. The machine as set forth in claim 2 in which the rolls have shafts rotatably carried by hearings in said frame; the bearings for the print roll constructed and arranged to permit said axial movement thereof; a cam disc having a cy-lindrically grooved periphery; a rotatable crank pin of short radius engaging the groove in said disc; and a high-ratio speed-reducer driven by said driving means and operatively connected with said crank pin.

4. A machine for applying carbon composition to webs of tissue for the manufacture of carbon paper with predetermined uncoated areas, said machine comprising a supporting frame, a fountain device carried by said frame and including a rotatably mounted fountain roll, a print roll, means for feeding a web of tissue past said print roll rotatable in synchronized rolling contact with said fountain roll and also with respect to said web to pick up a film of carbon composition from said fountain roll and apply it to said web, and means for oscillating said print roll with respect to the fountain roll and web and in the direction of its own axis and at an extremely slow rate as compared with the rate of rotation of the rolls and the rate of linear feed of the Web, wiping means in contact with said fountain roll to remove a cylindrical area of the film from the fountain roll to provide a desired pattern of partial coating application to the Web, and means for synchronously driving said rolls, said web feeding, and said oscillating means.

5. A method for substantially reducing the rate of Wear in a radial direction at any one point on the surface of a print roll while transferring at least one band of carbon composition film covering only a portion of the surface of said print roll to a web of tissue fed past said print roll whereby a predetermined pattern of partial coating is applied to said web, comprising the steps of applying from a supply source at least one band of film to part of said print r011 corresponding to the part of the web to be coated whereby a portion of the surface of said print roll remains uncoated, feeding said web of tissue past said print roll in contact with the surface thereof, and oscillating said print roll parallel to its axis and at an extremely slow rate as compared with the rate of rotation of said print roll to continuously change the axial position of said uncoated portion on the surface of said print roll and substantially extend the useful life of said print roll.

References Cited UNITED STATES PATENTS 2,066,780 1/1937 Holt 11744 2,402,559 6/1946 La Hatte et a1. 117--36.1 3,230,106 1/1966 West 117111 FOREIGN PATENTS 132,271 4/ 1949 Australia.

MURRAY KATZ, Primary Examiner. 

1. A MACHINE FOR APPLYING CARBON COMPOSITION TO WEBS OF TISSUE FOR THE MANUFACTURE OF CARBON PAPER WITH PREDETERMINED UNCOATED AREAS, SAID MACHINEF COMPRISING A SUPPORTING FRAME, A FOUTAIN DEVICE CARRIED BY SAID FRAME AND INCLUDING A ROTATABLY MOUNTED FOUNTAIN ROLL, A PRINT ROLL, MEANS FOR FEEDING A WEB OF TISSUE PAST SAID PRINT ROLL ROTATABLE IN SYNCHRONIZED ROLLING CONTACT WITH SAID FOUNTAIN ROLL AND ALSO WITH RESPECT TO SAID WEB TO PICK UP A FILM OF CARBON COMPOSITION FROM SAID FOUNTAWIN ROLL AND APPLY IT TO SAID WEB, AND MEANS FOR OSCILLATING SAID PRINT ROLL WITH RESPECT TO THE FOUNTAIN ROLL AND WEB AND IN THE DIRECTION OF ITS OWN AXIS AND AT AN EXTREMELY SLOW RATE AS COMPARED WITH THE RATE OF ROTATION OF THE ROLLS AND THE RATE OF LINEAR FEED OF THE WEB, MEANS FOR REMOVING A PORTION OF SAID FILM FROM CERTAIN OF SAID ROLLS TO PROVIDE A DESIRED PATTERN OF PARTIAL COATING APPLICATION TO THE WEB 